1. Field of the Invention
The invention pertains to a bearing bush system for a two-part steering shaft that serves for producing an axially movable and sealing connection between an outer steering shaft and an inner steering shaft and comprises a bearing bush, static and dynamic sealing means and a covering cap.
2The Prior Art
One known two-part steering shaft for utility vehicles comprises an outer steering shaft that consists of an outer tube and features a bearing bush that is integrated into its free end, as well as an inner steering shaft that is realized in the form of an inner tube and guided in this bearing bush in an axially movable fashion in order to compensate vibrations that occur during the operation of the vehicle and are transmitted to the steering shaft or to allow a length compensation of the steering shaft when tilting the driver's cab. The bearing bush should not only allow a free and vibration-damping sliding movement, but also ensure an adequate outward seal between the two concentrically arranged parts so as to prevent the admission of splash and washing water, as well as dirt, dust and sand particles.
In order to mutually seal the two steering shaft parts, it was already proposed to utilize a bearing bush arrangement with a shaft seal attached on the outer face of the bearing bush, wherein the peripheral sealing lip of this shaft seal rests against the surface of the inner steering shaft. The shaft seal is fixed with the aid of an elbowed holding sleeve. The static seal between the bearing bush and the steering shaft is realized with an O-ring that is arranged between the holding sleeve and the face of the outer steering shaft.
One disadvantage of the proposed solution can be seen in the high manufacturing costs and assembly expenditures for the bearing brush that consists of four individual parts in all. In addition, the O-ring may be excessively compressed by the holding sleeve such that it loses its elasticity and therefore its sealing effect that is based on this elasticity.